The Stomach: 8-30-13 (BIO 181) Flashcards
1
Q
- storage of ingested food
- mechanical breakdown of ingested food
- chemical breakdown of food via acid and enzymes
- production of intrinsic factor
A
four major functions of the stomach
2
Q
____ required for absorption of vitamin ____ in small intestine
A
glycoprotien; B12
3
Q
4 regions of the stomach
A
cardia
fondus
body
pylorus
4
Q
folds in the stomach lining that flatten upon expansion
A
rugae
5
Q
the lining of the entire stomach
A
simple columnar epithelium
6
Q
- located in the stomach and lead to gastric glands
- contain secretory products released by several different cells
A
gastric pits
7
Q
- most abundant near base of gastric gland
- secrete pepsinogen
A
chief cells
8
Q
- located primarily in the proximal portion of the glands
- secrete hydrogen ions, intrinsic factor, and mucous cells
A
parietal cells
9
Q
maintain acidity of stomach
A
hydrogen ions
10
Q
necessary for the absorption of B12
A
intrinsic factor
11
Q
cells that secrete mucous
A
mucous cells
12
Q
- glands in the pylorus
- contain enteroendocrine cells that secrete hormones
A
pyloric glands
13
Q
- produce gastrin
- stimulates secretions of the parietal and chief cells
A
G Cells
14
Q
- release somatostatian
- inhibits release of gastrin
A
D Cells
15
Q
production of acid and enzymes by the gastric mucosa can be
A
- controlled by the CNS
- regulated by reflexes of ENS
- Regulated by hormones of digestive tract
16
Q
- Cephalic phase
- gastric phase
- intestinal phase
A
three phases of gastric control
17
Q
- begins when see, smell, or think of food
- directed entirely by CNS
- prepares stomach to receive food
- lasts minutes and can be affected by emotional state
A
cephalic phase of gastric secretion
18
Q
- begins when food enters the stomach
- lasts 3-4 hours
A
gastric phase of gastric secretion
19
Q
gastric phase proceeds via 3 mechanisms
A
- neural response
- hormonal response
- local response
20
Q
- begins when chyme enters small intestine (several hours after eating)
- functions in the control of the rate gastric emptying into the small intestine
- involved neural and hormonal responses
A
intestinal phase of gastric secretion
21
Q
digestion in the stomach includes
A
- preliminary digestion of proteins (by pepsin)
- some digestion of carbs (by salivary amylase)
- lipids by lingual lipase
22
Q
during digestion, the stomach contents
A
- become more fluid
- pH approaches 2.0
- pepsin activity increases
- protein disassembly begins
23
Q
although ___ occurs in the ____, nutrients are not absorbed there
A
digestion; stomach
24
Q
- plays a key role in digestion and absorption of nutrients
- 90% of nutrient absorption occurs
A
the small intestine
25
the small intestine is composed of three parts
- duodenum
- jejunum
- ilium
26
- the segment closest to the stomach
- 25cm (10in) long
- mixing bowl that receives chyme and digestive secretions from the pancreas and liver
- neutralizes acids before they can damage the absorptive surfaces of the small intestine
duodenum
27
- middle segment of the small intestine
- 2.5 meters (8.2 ft) long
- location of most chemical digestion and nutrient absorption
jejunum
28
- the final segment of small intestine
- 3.5 meters (11.48 ft) long
- ends at the iliocecal valve, a sphincter that controls flow of material from it into the large intestine
ilium
29
-permanent transverse folds in intestinal lining that do not disappear when small intestine fills
plica circulares
30
increase surface area of epithelium
intestinal villi
31
- contains extensive capillary network
- contains lacteals
- lines by epithelial cells
- increase surface area of epithelial cells that form brush boarder
- have intestinal glands in between
- duodenal glands
intestinal villi
32
- lymphatic capillaries
| - transport materials that cannot enter the blood
lacteals
33
-glandular pockets located at the base of each intestinal villi
intestinal glands
34
- watery intestinal juice
- 1.8 L per day enter intestinal lumen
- moisten chyme
- assist in buffering acids
- keep digestive enzymes and products of digestion in solution
intestinal secretions
35
weak ___ ___ move chyme slowly from duodenum to jejunum
peristaltic contractions
36
- stimulates motility and secretion along entire small intestine
- accelerate movement along the small intestine
gastroenteric reflex
37
- allows materials to pass from small intestine to large intestine
- triggers relaxation of ileocecal valve
- accelerate movement along the small intestine
gastroileal reflex
38
- lies posteror to stomach
- extends from duodenum toward spleen
- bound to posterior wall of abdominal cavity
- wrapped in thin, connective tissue capsule
pancreas
39
head of pancreas
- broad
| - in loop of duodenum
40
body of pancreas
- slender
| - extends toward spleen
41
tail of pancreas
-short and rounded
42
- ____make up entire surface of the pancreas
- are separated by connective tissue
- contain blood vessels and branches of pancreatic ducts
- ducts branch repeatedly and end in pockets called pancreatic acini
lobules
43
- blind pockets that make up the exocrine portion of the pancreas
- lined with simple cubiodal epithelium
pancreatic acini
44
- endocrine tissues
| - scattered throughout acini (only 1% of pancreatic cells)
pancreatic islets
45
endocrine cells of the pancreatic islets secrete ____ and ____ into bloodstream
insulin; glucagon
46
___ cells and ____ cells of duct system secrete pancreatic juice
acinar; epithelial
47
pancreatic juice= pancreatic ____
secretions
48
- 1000 mL (1 qt) per day
- controlled by hormones from duodenum
- contain pancreatic enzymes
pancreatic juice
49
- a carbohydrase
- breaks down starches
- similar to salivary amylase
pancreatic alpha-amylase
50
-break down complex lipids
pancreatic lipase
51
break down nucleic acids
nucleases
52
- make up 70% of all pancreatic enzyme production
- secreted as inactive proenzymes
- activated only after reaching small intestine
- include proteases and peptidases
pancreatic enzymes
53
break down large protein complexes
proteases
54
break down small peptides into amino acids
peptidases
55
- the larges visceral organ (1.5kg; 3.3lbs)
- lies in right hypochondriac and epigastric regions
- is wrapped in tough fibrous capsule
- is covered by visceral peritoneum
- is divided into right, left, quadrate, and caudate lobes
the liver
56
___ lobe and ___ lobe dived by inferior vena cava
right; caudate
57
___ sits between right and quadrate lobe
gallbladder
58
___ blood vessels reach liver by traveling through the lesser omentum, the converge at the porta hepatis
afferent
59
venus blood from the ___ ___ vein
hepatic portal
60
___ lobes are made up of about 100,000 lubules per lobe
liver
61
- the basic functional units of the liver
- each is hexagonal in cross section and about 1 mm in diameter
- all separated by connective tissue
- contains six portal areas
liver lobules
62
portal area contains three structures
hepatic artery proper
hepatic portal vein
bile duct
63
branches from the arteries and veins deliver blood to the ___
sinusoids
64
blood then leaves sinusoids and enter the __ vein
central
65
central veins ultimately merge to form the ___ veins, which then empty into the inferior vena cava
hepatic
66
circulating levels of nutrients are adjusted by the liver cells
hepatocytes
67
- absorb solutes from plasma as blood flows through sinusoids
- secrete materials such as plasma proteins
selective absorption and secretion
68
- located throughout sinusoidal lining of each lobule
| - function in phagocytosis and storage
kupffer cells
69
liver secretes ___ fluid into a network of narrow channels (bile canaliculi)
bile
70
- collect bile from all bile ducts of liver lobes
| - unite to form common hepatic duct that leaves the liver
right and left hepatic ducts
71
bile flows from common hepatic duct to either:
- the cystic duct, which leads to the gallbladder
| - the common bile duct, which empties into duodenal ampulla
72
at the duodenal ampulla, the ___ bile duct meets the ___ duct and penetrates wall of duodenum
common; pancreatic
73
three major functions of the liver
- metabolic regulation
- hematological regulation
- bile production
74
composition of all circulating blood
- acts as the gate keeper of the blood
| - blood leaving the digestive tract enters the hepatic portal system and flows into the liver
75
- liver remoces and stores excess nutrients
- all liver cells extract nutrients or toxins from blood before they reach systemic circulation
- corrects nutrient deficiencies by mobilizing stored reserves or performing synthetic activities
nutrient metabolism and storage
76
removal of amino groups from waste to produce ammonia
deamination
77
after deamination, ammonia is then converted to ___ that can easily be excreted by kidneys
urea
78
limits the duration that drugs actually have effects in the body
drug inactivation
79
-ultimately stabilizes blood glucose levels
carbohydrate metabolism
80
- glycogen broken down into glucose
| - occurs when glucose is scarce or being used rapidly
glycogenolysis
81
___ blood glucose= hepatocytes convert glycogen to glucose
low
82
glycogenolysis can only occur in the
liver
83
when glycogen is broken down, it is released as ______ and is usually the starting phase of glycolysis
glucose-6-phosphate
84
- glucose is converted to glycogen
- occurs when glucose is in abundant supply
- high blood glucose = hepatocytes remove glucose from bloodstream and store it as glycogen
glycogenisis
85
- similar to glycogenolysis
- does not used glycogen to create glucose
- other carbs, amino acids, ect are used to synthesize glucose
- can only occur in the liver
gluconeogenesis
86
- triglycerides, fatty acids, and cholesterol
- low lipid levels=liver breaks down lipid reserves and releases them into bloodstream
- high lipid levels=lipids are removed and then stored
lipid metabolism
87
-excess amino acids removed and used to synthesize protiens, lipids, or glicose (for energy)
amino acid metabolism
88
- A, D, E, K, B12
| - absorbed from blood and stored in liver for future use when it is depleted from diet
vitamin storage
89
EX: iron is converted to ferritin and then stored
mineral storage
90
- kupffer cells remove old red blood cells, bacteria, and any badness from the blood
- can also trigger immune response as needed by the body
phagocytosis and antigen presentation
91
-hepatocytes make albumin as well as clotting proteins, and others
synthesis of plasma proteins
92
-absorbs and recycles hormones such as epinephrine, norepinephrine, insulin, thyroid hormone, steroid hormone, sex hormone and corticosteroids
removal of circulating hormones
93
- removal or ___
| - removal or storage of ___
antibodies; toxins
94
liver ___ bile and ___ it into the duodenum under neural and hormonal regulation
synthesizes; secretes
95
water and ions in bile ___ and ___ acids in chyme as it enters the small intestine
dilute; neutralize
96
bile ___ play a key role in lipid digestion
salts
